roslibdart

The is a fork of the original roslib by Eternali Conrad Heidebrecht (@Eternali), Artur Rymarz (@artrmz), TimWhiting Tim Whiting (@TimWhiting). roslibdart is a library for communicating to a ROS node over websockets with rosbridge. It is heavily influenced by roslibjs and follows the same structure. This fork is an effort to update the library and make it compatible to null safety, dart2 and ros2.

List of feature implementation statuses (essentially a list of features required to reach roslibjs's level)

• Core:
  • ROS connection object
  • Topic object (subscribe, unsubscribe, publish, advertise, unadvertise)
  • Service object (call, advertise, unadvertise)
  • Request object (provides typing and naming to any potential ROS request)
  • Param object (get, set, delete)

Usage

Install rosbridge

You can either

# install using apt-get
sudo apt-get install ros-foxy-rosbridge-server
#  or you can clone from github
cd ros_ws/src
git clone https://github.com/RobotWebTools/rosbridge_suite
cd ..
colcon build

Run ros bridge

cd ros_ws
source install/local_setup.bash
ros2 launch rosbridge_server rosbridge_websocket_launch.xml

Testing publisher

Run topic publisher

# Assume ros_ws is your workspace
cp -r rospackage/* ~/ros_ws/src/
cd ~/ros_ws
colcon build
source install/local_setup.bash
ros2 run tutorial publisher

Fire up flutter subscriber

cd example/subscriber
flutter run -d linux

Subscribe using roslibdart

ros = Ros(url: 'ws://127.0.0.1:9090');
chatter = Topic(ros: ros, name: '/topic', type: "std_msgs/String", reconnectOnClose: true, queueLength: 10, queueSize: 10);
ros.connect();
await chatter.subscribe(subscribeHandler);

Future<void> subscribeHandler(Map<String, dynamic> msg) async {
  msgReceived = json.encode(msg);
  setState(() {});
}

Testing subscriber

Run topic subscriber

ros2 run tutorial subscriber

Fire up flutter publisher

cd example/publisher
flutter run -d linux

Publish using roslibdart

ros = Ros(url: 'ws://127.0.0.1:9090');
chatter = Topic(ros: ros, name: '/topic', type: "std_msgs/String", reconnectOnClose: true, queueLength: 10, queueSize: 10);
ros.connect();
Map<String, dynamic> json = {"data": msgToPublished.toString()};
await chatter.publish(json);

Testing call

Run tutorial addtwoint service

ros2 run tutorial service

cd example/client
flutter run -d linux

Call a service using roslibdart

ros = Ros(url: 'ws://127.0.0.1:9090');
service = Service(name: 'add_two_ints', ros: ros, type: "tutorial_interfaces/AddTwoInts");
ros.connect();
Map<String, dynamic> json = {"a": 1, "b": 2};
Map<String, dynamic> result = await service.call(json);
msgToPublished = result['sum'];

Testing providing service

Fire up flutter service

cd example/service
flutter run -d linux

Run tutorial call

ros2 run tutorial client

Run the client from shell

ros2 run tutorial client 2 3

Provide service using roslibdart

ros = Ros(url: 'ws://127.0.0.1:9090');
service = Service(name: 'add_two_ints', ros: ros, type: "tutorial_interfaces/AddTwoInts");
ros.connect();
await service.advertise(serviceHandler);

Future<Map<String, dynamic>>? serviceHandler(Map<String, dynamic> args) async {
  Map<String, dynamic> response = {};
  response['sum'] = args['a'] + args['b'];
  return response;
}

Links

• ROSBridge Protocol v2.0.
• Original roslib library from Conrad Heidebrecht
• RosBridge server implementation
• roslibjs example